


into the new world

by lapeace



Category: Katekyou Hitman Reborn!, 僕のヒーローアカデミア | Boku no Hero Academia | My Hero Academia
Genre: Adult Vongola Family, Crossover, F/M, Gen, Hibari Kyoya Adopted the Bakusquad, M/M, Origin Trio Centric, Parallel Universes, Sawada Tsunayoshi Adopted the Origin Trio, Senior High School Big Three, Villain Uraraka Ochako, Villain Yagi Toshinori | All Might, boss!Tsuna
Language: English
Status: In-Progress
Published: 2020-12-18
Updated: 2020-12-18
Packaged: 2021-03-10 17:40:24
Rating: General Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 3,501
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28141029
Author URL: https://archiveofourown.org/users/lapeace/pseuds/lapeace
Summary: U.A's big three Midoriya Izuku, Bakugo Katsuki, and Todoroki Shouto are chosen to participate in a mission in Italy as one of Japan's hero representatives who will help apprehend the worldwide terrorist group Millefiore led by Byakuran.  There was a miscalculation on their part though. By the time they fully realized the full extent of Byakuran's quirk, they were already sent to a different world.The only connection they have left from their own world was unfortunately given by two young mafia bosses Tsunayoshi Sawada of the Clams and Ginny Farfalla of the Butterflies.
Relationships: Bakugo Katsuki & Hibari Kyoya, Bakugou Katsuki/Kirishima Eijirou, Hibari Kyouya/Original Female Character(s), Midoriya Izuku & Ginny Farfalla (Original Character), Midoriya Izuku & Sawada Tsunayoshi, Midoriya Izuku/Uraraka Ochako, Origin Trio & Sawada Tsunayoshi, Origin Trio & Vongola Family, Sasagawa Kyouko/Sawada Tsunayoshi, Sawada Tsunayoshi & Todoroki Shouto, Todoroki Shouto/Yaoyorozu Momo
Kudos: 26





	1. the big three in a pinch

**Author's Note:**

> I'm not sure where I'm going with this. Lol. Anyway, I often see FF where Tsuna or the Vongola Fam is in the MHA universe but seldom the reverse treatment so that's that, I guess?

Graduating heroes of U.A, Deku, Dynamight and Shouto didn't mean to make a grave mistake by moving head first amongst other pro-heroes. They can't help it. They have better mobility more so than the others and they are so focused with the goal: to apprehend the villain Byakuran as soon as they can. And it's supposed to work too since Byakuran was already too weak to move by the time they almost got him. They were, unfortunately, wrong. The three heroes were suddenly struck with what seems to be a white dragon the moment they advanced on Byakuran. 

They knew they weren't dying, of course. They felt no striking pain from the white dragon. Instead, it's an altogether new feeling as if being sucked into some void. It was also confusing. Athough they knew that they were being sucked, it didn't hurt that much at all. Whether Byakuran's quirk is too weak or they're just too consumed with adrenaline, they are not sure.

Deku's head is dancing with information. What is this quirk really? They thought Byakuran's quirk was premonition and mind reading because everytime heroes try to get a hand on him, he always have a counterattack as if he already anticipated what's going to happen. He also have this vast knowledge about many heroes' quirk. Yet at that time, he was already too weak to move and even Deku saw him almost crawling to the ground after receiving continuous damage from various heroes. The trio didn't even need to say anything. They knew how their mind works and with just a look in each other's eyes, they decided to end it once and for all. So what went wrong?

As hard as Deku tried, he couldn't claw his way out. Dynamight and Shouto are now nowhere to be seen. 

The last thing he remembered before passing out was being embraced by orange flames and dancing butterflies. This added to his confusion—he knew the owners of these quirks. Why are they doing this?

Meanwhile, said owners of the orange flames and butterflies was already too tired to move. They had to conceal themselves from both villains and heroes because of their titles and it was physically taxing to manage the feat. They could only watch as three heroes dissapear before their eyes. They did two things though. Using their combined quirks, they basked the trio with protective orange flames and gave them butterflies so they could find their way home.


	2. todoroki meets the sky

**Summary for the Chapter:**

> The Origin Trio was separated upon coming to a new world.
> 
> In which Todoroki Shouto was bested by a man named Sawada Tsunayoshi who produces fire and ice just like him; and encountered Yaoyorozu Momo who seemed disgusted with him (but he's going to pretend that he's not hurt nor offended).

Shouto was in an abandoned building when he woke up. He tried to get up as soon as he can but failed. He was still disoriented. He can feel the shaking of the whole place and hear the rumbling sounds of crashing buildings but that's all he knew. His communication device was broken so he can't call anyone about the current status.

They had assumed that Byakuran's quirk was premonition but since they still lack data, Shouto was now thinking that it's probably different from that. Maybe Byakuran's quirk allows him to teleport anything or anyone instead? Shouto can't really wrap around his head about the man's quirk after all. He just wished that he's not too far from the others. He tried to recall the events before passing out, planning to get back on the field the moment he feels better.

Italian pro-heroes Knife Prince and Umbrella Man subdued Byakuran using their quirks, that's the first thing he notes of. 

Then a subordinate of Byakuran who he knew as Lightning Gamma electrocuted the two pro-heroes but Luss-Sun guarded them using his healing quirk.

Then there came pro-heroes Squalo and Xanxus who simultaneously attacked him. Squalo with his endless blade and Xanxus with his dual guns.

By that time, Byakuran was almost crawling on the ground but the pro-heroes from the Italian team evidently still needs a lot of assistance. Byakuran could not be put down easily and his wings are probably doing most of the job. The heroes closest to him are having a hard time.

That's where he, Midoriya and Bakugo came in. At that time Todoroki and Froggy Fran was fighting a mermaid and lizard looking villains. Froggy Fran assured him that he can handle those two so he quickly shifted his focus to Byakuran knowing full well that his two friends will be there to support him.

The moment the three of them got close, Byakuran smirked and his wings suddenly tansformed into a white dragon. When it roared, the trio was sucked into a void.

Then here.

The moment Shouto got his bearing, he got up and explored the building. The area he was in was okay enough but outside, everything was in ruins. He was in a top floor of a high-rise building.

The other buildings were damaged really bad. Dark smokes were rising in many areas and fine suds were raining on him.

Weird lights of red, blue, yellow, green, violet and indigo were all over the place.

What is this? Shouto is not sure. This is probably a different area from where the main battle was but he jumped and propelled himself towards the closest tremor planning to assist any hero he can find. This is not the time to pursue Byakuran anymore although he didn't want anything more but to do that.

As he was propelling himself, huge debrees of a crashed building rained on him. He immediately protected himself from the damage but his senses perked up.

Though it was faint, he can hear someone screaming and struggling below. He then made a huge block of ice and slide down to inspect where it came from. By now, adrenaline is slowly pumping on his system again. He haven't seen any villains or heroes yet so something weird must be happening. He had no idea where he was and had no knowledge about the battle in this particular area. He needed more information or risk making miscalculation again.

Suddenly, there was no time to get information as he saw a huge Nomu advancing on the main road.

This was impossible.

The Nomus were apprehended a year ago by pro-heroes after the fall of All For One and the League of Villains. He briefly remembered the wars that led up to all the Nomus eventual imprisonment. Those were trying times and a lot of sacrifices were made. And although it was one of the hardest phase in his life, his memories weren't mangled. Nomus should not be running around here.

Without missing a beat, Shouto gain speed tailing the Nomu. Surprisingly, the Nomu made no advances as he approached and using his Flashfire Fist, he shoot it straight at Nomu's core. Knocking it out in the process.

The Nomu didn't attack him. Really, what is happening? 

Shouto went up again wanting to observe the surroundings but before he could even land in a building, he saw it. 

A larger Nomu was making its way to the highest skyscraper in the area. Destroying everything its huge body can touch. But the Nomu's presence itself was nothing compared to the twist in the gut he suddenly felt upon seeing who it was after.

Yaoyoruzu was running as fast as she can away from the Nomu. Her hair disheveled and her body covered in bruises. 

She was not supposed to be here, Shouto thought to himself. She was supposed to be in the hospital resting. She's not even wearing her hero costume. What's with that black suit and skirt? And what's with that small gun? Why not a bazooka?

Shouto is a calm man but seeing his classmate—top of the class, at that—running with just a small gun infuriates him. He did not expect this from Yaoyoruzu of all people. It was reckless and dangerous. This was unbecoming of her as a hero. And what would he do to himself if something happens to Yaoyorozu?

Shouto had never felt this much annoyance towards Yaoyorozu. That and a good amount of fear. His heart was heavily pounding as he jet-flies towards her.

The gears on his head shifted: save Yaoyorozu first then assist other heroes at whatever the hell is happening here.

The Nomu threw a huge chunk of debree towards Yaoyorozu and she was almost hit in the head. At that moment, the girl abruptly stopped running and turned around facing the Nomu. She held her feet on the ground, lifting her gun in a shooting stance. Her eyes were sharp, hands steady and if Shouto did not know better, it's as if it would take at least five more Nomus before anyone can shake her in her place.

But he did know better despite his faith on Yaoyorozu. The moment the Nomu reach her, she'll be gone and he'd rather die than allow that to happen.

He increased his pace, simultaneously cooling his body while controlling the jet flames on his foot. He skidded along the road then with a sudden jerk of his foot allowing him to add more juice in his jet, he grabbed Yaoyorozu from the waist and enclosed the Nomu into a huge ice.

The force from the action upset Shouto's balance and he almost loose his footing while carrying Yaoyorozu in his arms but he managed after making an ice support.

Momo was wide-eyed and frantic. She immediately jumped away from the enemy then looked for her gun but to her dismay, she accidentally let go of it when said enemy saved her.

But why? The Nomu was frozen in place and the man was looking at her with surprise and a bit of annoyance. Why did this man saved her again?

Shouto was almost offended. He didn't expect Yaoyorozu to thank him given their situation but the sudden jerk of her body the moment he touched her doesn't sit right with him. As if she was scared of him. As if he was a villain. He can't remember if he'd done something to offend her. Before they went to Italy, he even visited Yaoyorozu in the hospital but she was asleep and didn't want to wake her up so he only left the flowers he brought in her bedside table. He even left a short note wishing for her fast recovery. He didn't want to be offended, really. But he didn't like Yaoyorozu's slight disgust with him right now. It just felt so wrong.

Annoyed he said, "What is wrong with you and what are you doing here?"

Momo couldn't reply. He's speaking to her as if they knew each other and as if she had hurt his feelings. Momo almost trusted him once but never again. She stood on her ground daring him to attack but he didn't.

Instead, he glanced to the Nomu then back at her. "Do you have any plans on how we can restrain this one? My ice won't hold him for too long."

What is he talking about? Those Nomus were produced by them. He can control them. Is this part of some scheme?

There was a click on Momo's ears and she realized that the communication link is back. Without even leaving her gaze on their enemy, she contacted her superior.

"Sir?" 

"I'm here," Mr. Gokudera replied immediately.

"I'm face to face with the Ice and Fire."

"Hold your ground unless he attacks. Tenth is on the way," Gokudera ended.

Shouto is torn between shaking Yaoyorozu to her senses and guarding the Nomu against them. She just talked to someone and referred to him as Ice and Fire. Seriously? He was continuously putting layers of ice on the Nomu but it was resisting and slowly cracking the layers. If Yaoyorozu won't snap out of it then the best course of action is to either wait for reinforcement or retreat since there's also the possibility that the Nomu he knocked out earlier will come back for him.

Shouto glanced at Yaoyorozu who was still on guard. Maybe this was Byakuran's quirk? To make her forget about him? What if it wasn't just her? What if everyone else forgets him?

He moved closer to the Nomu in full concentration. If they can't retreat or no reinforcements came, the next best course is to use his Prominence Burn. He needed more time to gather his strength for that though and simultaneously using his ice and fire is finally taking a toll on him.

The ice caging the Nomu finally broke in full. Shouto grunted as he pick up his pace in creating the layers of ice but to no avail. 

Yaoyorozu stepped back as the Nomu went directly for her. Entirely disregarding Shouto's presence.

Shouto bit his tongue—trying to control his panic. What is wrong with this Nomu? He boosted up his left side, concentrating all the heat he can conjure in his fist.

He was in despair. It was happening all too fast.

He's not gonna make it and Yaoyorozu will be smashed into pieces.

The Nomu's brawled claws are now only at hands length from Yaoyorozu's face.

Just then, the Nomu was again enclosed in a cage of ice and it wasn't his own doing.

Shouto looked around for the source and saw a glimpse of a man with brown hair. A huge ember of fire is glowing on his head. Before he could even react, the man grabbed his left arm and threw him on the ground.

Shouto broke free by covering the road in ice and sliding away from the new comer but his speed wasn't enough. The man immediately attacked him with his gauntlet covered in flames. The impact was too strong Shouto felt blood in his mouth. 

In quick retaliation, Shouto tried to freeze the man's hands but failed. When that didn't work, he used his left hand and shoots fire straight to the man's face. To his dismay, it's as if the man could read his moves so he immediately gain some distance.

There was no time to even take a proper breather. Shouto was sure that with one wrong move, this man might just kill him.

There was no other way but to retreat. He couldn't take this man alone without knowing his quirks and with very limited energy to fight. He looked around for Yaoyorozu. When he saw her just a few feet behind him, he started shooting fire on the man's direction. Hoping to distract him. Hoping that the smokes would cover them as soon as they run.

He quickly grabbed Yaoyorozu's hand.

Momo was shocked when the enemy grabbed her on the wrist and pulled her in a run. She slapped his hands as soon as she realized what's happening but the man wouldn't let go.

"Let go of me!" She yelled at him. Now slapping him in the face instead.

To say that Shouto was astounded is an understatement. No, he wasn't astounded, really. It was something beyond that. He is confused and hurt and angry at Yaoyorozu for acting so strange. He let go of her hand but did not say anything. What more he could say?

Once the man finally let go of her, Yaoyorozu suddenly felt bad. It was in the look in his eyes. As if she had betrayed him.

She stepped back away from him. Why did she felt so guilty? She gave him a chance once but he ruined it so she shook her head. She looked at Sawada Tsunayoshi who was still suspended in the air as if observing the Ice and Fire.

"Yaoyorozu-san, please move away," she heard Sawada-san from her commlink. She nodded in his direction and moved away. Finally having the time to prepare the device needed to subdue the Nomus.

Shouto snapped back his attention to the man who is evidently observing him. He'll deal with Yaoyorozu later.

He created an ice wall as he concentrate a huge fireball on his left hand. The ice wall cracked as soon as it was built. Shouto moved away as a huge blast of fire came at him while still concentrating in making a huge fireball.

The man propelled himself downwards to his direction. That's when Shouto aimed his left hand at him and released his fireball.

He cooled down his body and watched as the brown haired man stayed in place. His two hands were positioned to form a diamond shape in the center. Shouto eyed him curiously. Is he planning to receive his fire directly? Was this man mocking him?

But at the last minute, the man moved away and then dived towards Shouto at great speed. Shouto felt the adrenaline and without even second thinking, he made an ice makeshift ready to attack as well.

Ice on his foot and fire in his hands.

With a huge blast of fire, the battle ended. Momo was briefly blinded as the two different kinds of flames collide.

Shouto couldn't move. His whole body except his head was covered in ice. He had lost. He tried to heat up his body but the ice he was enclosed with is not melting.

The man walked forward and regarded him with calm eyes. There was something in his eyes that bothered Shouto. It was as if he could read his heart, if that even makes sense.

As the man studied him with curiousity, Shouto looked back at him, his gaze full of defiance.

He has a job as a hero and he will not be put down like this. The battle is not over.

Yaoyorozu walked towards them and got the man's attention, "Sawada-san, I'm done tweaking the device."

The man called Sawada only nodded. And to Shouto's great surprise, he placed his gauntlet in the ice he created then melted it. Shouto looked at him curiously. Still on guard.

"What are you doing, Sir?" Yaoyorozu asked in an almost whisper.

Sawada shook his head. His smile was resigned before answering, "It wasn't him."

Shouto's head is starting to get hurt. What the hell is seriously happening?

"I didn't realize soon enough. I'm sorry for attacking you. You even tried to protect my comrade."

The ice finally melted and Shouto is once again free to move. He then gazed upon the Nomu that was frozen by this Sawada-san. It wasn't breaking. It wasn't cracking at all. If anything, it's as if it was more of a crystal than an ice.

Tsuna understands perfectly why the teenager in front him was skeptic. But he was sure. He looked exactly the Todoroki Shouto they were hunting but this is a different man. He was blindly running earlier and he was almost ashamed of himself for not realizing immediately. He can trust this man and he was sure of it.

"We are still trying to contain the Nomus and I think you'd be willing to help us," he said with a friendly tone. "Ms. Yaoyorozu here and my storm guardian came up with a plan to gather all the Nomus in front of the highest skyscraper. Then I'll use my Zero-Point Breakthrough to seal them."

"I don't know what's happening," Shouto found himself saying. He was surprised for voicing it out but Sawada only regarded him as if silently telling him that he understands.

"We can sort that out later," Tsuna replied.

He was right. Shouto can sort this out later. He is a hero and he has a job to do. He stood up more confidently and with ease. The first time he actually felt more himself from the moment he woke up.

"Yaoyorozu-san is the only one who knows the wave frequency that attracts the Nomus. Please protect her until you get to the skyscraper. Me and my comrades will guide the Nomus in that direction. Can you do this alone?"

Shouto nodded. Yaoyorozu looked uncomfortable but didn't say anything. Shouto finally realized why she was running towards that direction earlier. She was even willing to stood her ground at the cost of her life. He felt bitter and disappointed with her right now. The Yaoyorozu he knew would be willing to lay out her life for anyone but not before exhausting all the other possibilities for survival. If only she had used her quirk then there wouldn't be any problem.

"I can freeze them for a few minutes or seconds but you have to come as soon as you can to seal them with your weird ice," Shouto said as he followed Yaoyorozu.

Tsuna almost laughed to himself as he watch the two running. Weird ice? He composed himself and sighed. Calling it weird ice does makes sense. He said earlier that they can sort this out but he's not sure anymore. He couldn't find the mastermind Toshinori Yagi and this would pose as a big problem.

He's glad that both Enma and Nami's family are working with the Vongola. Even taking charge in their pursuit in Italy. He was also glad that Hibari and his foundation was backing up the mission in Japan.

He just hoped that everyone remains safe.

**Notes for the Chapter:**

> I asked my sister to read this before I post it and she said non-verbatim: "But why did Tsuna did not just consumed Todoroki's fire with zero point breakthrough revised so he can use it for himself??? And why can't Shouto melt Tsuna's ice?? This is stupid."
> 
> In which I replied: "Seat down, Amanda. Todo doesn't have a dying will flame and Tsuna can only consume it if it's a dying will flame. Shouto cannot melt it because his flames are not a dying will flame. You dumb."
> 
> So she said it's okay. But she still calls it stupid because I'm her sister and I wrote it.
> 
> And all I said was, "Uh-huh. YES."
> 
> Anw, thank you for coming here. :D


End file.
